Genetic diversity and population structure analysis of short‐day onions using molecular markers in association with resistance to Fusarium basal rot

In this research, we analyzed Random Amplified Polymorphic DNA (RAPD), Inter Simple Sequence Repeats (ISSR) and Sequence-related amplified polymorphism (SRAP) markers to evaluate the genetic diversity of eighteen different onion genotypes with various resistant levels to FOC. The results showed that the polymorphism means between RAPD primers was 61.11 to 81.81%; ISSR primers, 62.50 to 81.81%; and SRAP primers, 56.25 to 76.25%. Overall, by assessing MI, PIC, I and H indices, indicating the best thrive in evaluating the genetic diversity of the related onion populations. There is a significant correlation between the generated dendrograms based on similarity matrices. The classification pattern in dendrograms shows a corresponding correlation with the FOC disease severity bunches. So in all three markers studied, 'Saba' and 'Saba - HS', the most resistant ones to FOC disease, were grouped in a branch, and the 'Sahar - HS' and 'Golden Eye', the most susceptible ones were also grouped in another branch separately. This finding indicates that predominant primers act as markers linked to resistance gene(s) against FOC, which can be used to select onions resistant to FOC disease in any breeding scheme.